1. Field of the Invention
The present invention relates generally to water well pumps and, more specifically, to a vertically-stacked, multi-staged, regenerative turbine pump for a water well which can be solar powered, AC or DC powered, or solar/wind energy powered.
2. Description of the Prior Art
In most rural environments, water wells are a given necessity. Well pumps are the modern day equivalent of windmills, which were historically used to move water from one location or one depth to another. In addition to providing water for such everyday activities as showering, doing laundry and running the dishwasher, well pumps are also used at the present time for such diverse purposes as irrigating crops, providing livestock with water, supplying water to remote locations, or for acting as heating and cooling mechanisms for geothermal systems.
Two of the commonly used well pumps at the present time are the electric submersible pump and the reciprocating plunger well pump. Various designs of reciprocating plunger well pumps have been developed of more or less the same general type having a pump which is mounted at the lower end of a well pipe string and also having a reciprocating plunger or piston connected to an elongated rod extending to an actuating mechanism at the earth's surface. The pumps also include a cylinder in which the plunger reciprocates to displace fluid from a plunger cavity and is controlled by cavity inlet and discharge valves mounted on the cylinder and on the plunger, respectively.
In spite of the relatively highly developed state of the art in reciprocating plunger well pumps, certain problems in the operation of these pumps persist. These types of pumps load and release with each cycle. In particular, when the pumps are stopped, water hammer develops, which is an unwanted noisy and shaking condition of the pump. Further, the balls in many pumps are steel. Therefore, when the seat that the ball rests on becomes worn and damaged by the constant beating from the ball, erosion from abrasives, corrosion, chipping, or flaking, the steel balls cannot seal the pump and there is unwanted water leakage related to the inability to perform required, specialized service.
As a result of some of these shortcomings, a large number of homes in the United States use electric submersible pumps at the present time. The electric submersible pump is installed in the wellbore, below the water line. A small electric motor is also installed in the wellbore, usually below the pump itself, and an electric cable is attached to the motor and run to the well surface. Piping is then fitted from the pump, through the length of the wellbore and into the home. Submersible well pumps may be set hundreds of feet in depth within the wellbore. Activation of the electric motor though the downhole cable causes the pump to push water upwardly through the piping to the well surface.
Submersible pumps are typically long cylinders some three to five inches in diameter and two to four feet long. Such well pumps may be powered by alternating current, solar power, wind power, water power, or even manually. In some remote locations, it is not practical to have an electrical power supply from an electric power company. Therefore, alternative sources of energy, such as the use of solar energy, batteries or wind power are preferred. This is especially true in the case of such applications as pumping water at remote locations, such as to water livestock.
One type of water pump of the general “turbine-type” classification are the so-called centrifugal pumps. Centrifugal pumps are quite well known and are used in a variety of different fluid pumping applications. However, such turbine-type pumps can be inefficient in building a pressure head for a given flow rate and require more electrical power to operate than a positive displacement pump of equivalent capacity. In the case of solar-powered pumps, this requires a greater number of solar cells to operate. This is a disadvantage because the solar cells are expensive and more area must be provided to accommodate them.
There are a large number of references in the patent literature to submersible well pumps. For example, U.S. Pat. No. 4,162,137 shows a submersible, hydraulically-driven pump rotating about a vertical axis, the pump having a short shaft between the hydraulic motor and the impeller of the pump. The apparatus uses a cofferdam around the hydraulic pipe and the hydraulic motor, formed as three consecutive chambers around the shaft.
U.S. Pat. No. 6,361,272 B1 shows a submersible centrifugal pump for downhole pumping of methane-saturated water from wells drilled in coal formations. The pump has an electric motor-driven vertical shaft with centrifugal impellers distributed there along, each impeller being located in a stationary diffuser within the pump to form a multi-stage pump.
U.S. Pat. No. 6,926,504 shows a submersible electric pump comprising a stator and a stator housing, along with an armature and an armature housing. The stator and armature are assembled in connectable and interchangeable sections called “modules” that can be attached in series.
U.S. Pat. No. 5,201,848 is an electrical downhole pump for pumping fluids from a deep well. The pump has a relatively small diameter pump housing which is suspended from a tubing string and including a series of impellers and diffusers. The impellers are mounted on a vertical shaft connected to a motor for driving the impellers relative to the diffusers on the housing. A first group of impellers are arranged to move freely longitudinally on the shaft while a second group are fixed to the shaft to prevent relative longitudinal motion.
The above references are intended merely to be representative of the large variety of different submersible pump devices which have been employed in the past and which suffer, in one way or another, from the various shortcomings discussed above. Efforts to eliminate the above-mentioned shortcomings, while providing a well pump which is relatively inexpensive to manufacture and is reliable in operation, have not been entirely successful and further improvements in such pumps have long been sought. It is to these ends that the present invention has been developed, particularly for use in water wells, although conceivably other fluids could be pumped as well.
A need exists, therefore, for an improved water well pump which is economical to manufacture and which is reliable in operation, which can conveniently be powered by harvested energy sources, such as by solar power with a battery backup, by solar power directly, by wind power, etc.
A need also exists for such a pump which has particular application for lower capacity, high head applications, such as a water well for watering livestock at a remote location with a low production well.
A need also exists for a water well pump which incorporates regenerative turbine technology into traditional electric submersible pump applications.